Abstract Biodiversity loss is a significant global challenge, driven by human activities. In this sense, regional and updated Red Lists are essential to document threatened species and guide efficient management. This study aimed to review the threatened plant species list in the state of Paraná, Brazil, contributing to conservation planning and public awareness of plant diversity in the region. We compiled a list of threatened species occurring in the state, from the CNCFlora official evaluation based on IUCN guidelines, as well as their growth form and geographic distribution. A careful taxonomic evaluation was also performed based on herbaria databases, to update putative synonymous and to verify occurrence. After that, we compared our verified species list with the official state’s Red List, lastly reviewed in (CNCFlora 2014). We mapped the species occurrences and analyzed the distribution of collections over time. We found 300 threatened species across 79 botanical families, adding 160 species to the previously available state's Red List. Moreover, 13 species from the previous Red List had no verifiable occurrences or threat category in the state, based on both herbaria collections and scientific literature. Herbaceous species are prevalent within the threatened species, followed by arboreal and shrub species. The distribution of threatened species is not uniform across the state’s area, with clusters in urban areas. This study highlights gaps in knowledge and emphasizes the importance of ongoing monitoring and conservation efforts to safeguard biodiversity.
Rauber et al. (2026) studied this question.